Delta-modulation signal processors: linear, nonlinear and mixed

ABSTRACT

Disclosed are nine functional circuits for the direct processing of a delta-modulated pulse stream. These circuits can be integrated separately, as standalone circuits, or integrated into a programmable, functional unit to form a system on chip (SoC). Disclosed functional units are low-power consuming, simple, reliable and inexpensive. Because of the non-positional nature of delta-sigma modulated (DSM) pulses and the averaging nature of the demodulator, disclosed circuits are tolerant to catastrophic errors, which is not the case with ordinary n-bit DSP hardware.

CROSS REFERENCES TO RELATED APPLICATIONS

Dj. Zrilic, U.S. Pat. No. 5,349,353, Date of patent: Sep. 20, 1994

Dj. Zrilic, U.S. Pat. No. 6,285,306 B1, Date of Patent: Sep. 4, 2001

STATEMENT REGARDING FEDERALLY SPONSORED R&D

These research results are not sponsored by Government grants.

NAME OF PARTIES TO A JOINT RESEARCH AGREEMENT

Individual project of Dr. Djuro G. Zrilic

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the direct processing of delta sigma modulated (DSM) and linear delta modulated (LDM) pulse streams. The sensing signal (analog input signal) is first converted into a one-bit high density (oversampled) pulse stream using DSM or LDM oversampled analog-to-digital converter. To implement a particular linear or nonlinear function, dedicated circuits have to be developed. Thus, the field of this invention is a pulse signal processing of one-bit non-positional delta modulated stream. It belongs to a wider class of digital signal processing (DSP) in the electrical engineering field.

2. Description of the Prior Art

The conventional method of DSP of a DSM pulse stream is achieved by using a decimation technique to interface with existing n-bit DSP hardware. Existing n-bit DSP hardware is bulky, power consuming, and prone to errors. Typical DSP hardware consists of a micro-processor and supporting n-bit communication lines with centralized control and synchronization. This hardware is not suitable for sub-micron technology because n-bit processors are hierarchical systems (every bit is weighted), and when the most significant bit (MSB), or sign bit is in error, a catastrophic malfunction can happen. To take advantage of the non-positional nature of a DSM pulse stream, there were several attempts to develop circuits for linear processing of a DSM pulse stream.

The earliest publications on the use of DSM in signal processing comes from Lockhart [1]. Digital filter coefficients are made of resistive networks. A similar idea is used by Lockhart and Babary [2] to implement an infinite impulse response (IIR) filter using a recalculating shift register. In both publications resistors are used to add filter coefficients.

Publications of Peled and Liu [3], [4] use ordinary DSP hardware to implement delta-modulated based digital filters. The implementation of filter coefficients is achieved using read-only memory (ROM).

In 1978 Lagoyannis [5] proposed a new method for multiplying delta-modulated signals by a constant. He implemented a digital circuit for direct multiplication of a delta modulated sequence.

In 1978, Locicero et al. [6] proposed a method for direct processing of adaptive delta-modulated (ADM) signals. By operating on the serial DM bit streams, sum, difference and product can be obtained in PCM and DM format. An arithmetic processor uses ordinary DSP hardware.

In the period 1978-1985 Kouvaras published number of papers related to linear processing of a delta-modulated stream. In reference [7] Kouvaras proposed a new method with which is possible to find a delta-modulated signal of the half sum of two analog signals through direct operation of their delta-modulated form. He proposed hardware implementation of a delta adder and did error analysis of the proposed circuit. In reference [8] Kouvaras proposes a digital circuit for doubling the amplitude of a delta modulated signal. In fact, by using a delta doubler, it is possible to overcome the problem of attenuation of one-half which the delta adder introduces [7]. In reference [9] Kouvaras proposed several circuits for the direct multiplication of delta-modulated signals by constants. In addition to a non-recursive form, Kouvaras proposed a recursive form of multiplier. In reference [10] Kouvaras proposed a new modular multi-input network for direct arithmetic operation on DM signals. In reference [11] Kouvaras proposed a technique for the reduction of the quantization noise in the direct processing of a DM pulse stream. In reference [12] Kouvaras proposed the modular network for the direct addition of DM signals with minimum quantization noise.

Lagoyannis and Pekmestzi proposed multipliers of two DM sequences [13]. These multipliers provide the product in DM sequence form. These multipliers were used in the implementation of a parallel type of digital correlator.

In reference [14] Zrilic et al. proposed the implementation of a ternary delta adder and ternary delta multiplier for the implementation of digital filters. In reference [15] Freedman and Zrilic proposed a new algorithm for linear and non-linear processing of a DM pulse stream. In reference [16] Zrilic proposed a number of circuits for linear, nonlinear and direct processing of a DM pulse stream. In his patents (U.S. Pat. No. 5,349,353 and U.S. Pat. No. 6,285,306 B1), Zrilic disclosed the number of circuits for linear, nonlinear and mixed processing of a DSM pulse stream.

In reference [17] Wong and Gray present two methods for building FIR filters based on single-loop and two-stage DSM encoding. These filters do not require multipliers.

Horianoupulos et al. [18] proposed a design technique for hardware reduction in delta modulated FIR filters. This method takes advantage of the special characteristics of DM filters in order to reduce noise.

Johns and Lewis [19] designed and analyzed delta-sigma filters by eliminating all multi-bit multipliers through the use of re-modulating internal filter states.

BRIEF SUMMARY OF THE INVENTION

The present invention introduces a number of novel circuits for direct processing of DSM pulse stream. It is based on linear, nonlinear and mixed analog/digital processing using mainly digital circuitry. The present invention includes:

-   1. Method and apparatus for squaring operations (digital     implementation) -   2. Method and apparatus for squaring operations (mixed     analog/digital implementation) -   3. Method and apparatus for DSM based AC-DC conversion -   4. Method and apparatus for multiplication of two DSM pulse streams     (mixed implementation) -   5. Method and apparatus for multiplication of two or more DSM     streams (digital implementation) -   6. Method and apparatus for RMS-to-DC conversion -   7. Method and apparatus for multiplication of a DSM stream with a     constant -   8. Method and apparatus for addition of multiple DSM sequences -   9. Method and apparatus for correlation of two DSM sequences -   10. DSM System on Chip (SoC)

It is therefore a primary objective of the present invention to provide a number of circuits necessary for DSP of DSM pulse streams.

It is another objective of the present invention to provide simple and reliable circuits which will significantly enhance applications of DSM signal processing in different application areas.

It is still another objective of the present invention to reduce power consumption of DSM processing elements in applications where power consumption is a critical factor.

It is still a future objective of the present invention to provide a simple and inexpensive VLSI design.

It is still a future objective to design the system on a chip (SoC) which includes multiplexed sensors array, DSM ADC and newly proposed circuitry for functional processing of DSM pulse stream.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A shows a block diagram, with belonging waveforms of operation, of a DSM circuit for the squaring operation of an analog input signal (digital implementation) as shown in FIGS. 1C, 1D and 1E. FIG. 1B shows the frequency spectra of the signal in FIG. 1D.

FIG. 2A shows a block diagram, with belonging waveforms of operation, of a DSM system for the squaring of an input analog signal (mixed analog/digital implementation) as shown in FIGS. 2C, 2D and 2E. FIG. 2B shows the frequency spectra of the signal in FIG. 2D.

FIG. 3A shows a block diagram, with belonging waveforms of operation, of a DSM system for AC-DC conversion (digital implementation) as shown in FIGS. 3B and 3C.

FIG. 4A shows a block diagram, with belonging waveforms of operation, of a DSM system for multiplication of two analog signals (mixed analog/digital implementation) as shown in FIGS. 4C and 4D. FIG. 4B shows the frequency spectra of the signal in FIG. 4D.

FIG. 5A shows a block diagram, with belonging waveforms of operation, of a DSM system for the multiplication of two analog signals (digital implementation) as shown in FIGS. 5C and 5D. FIG. 5B shows the frequency spectra of the signal in FIG. 5D.

FIG. 6A shows a block diagram, with belonging waveforms of operation, of a DSM system for RMS-DC conversion (digital implementation) as shown in FIGS. 6B and 6C.

FIG. 7A shows a block diagram, with belonging waveforms of operation, of a DSM system for the multiplication of a DSM pulse sequence with a constant greater or less than one (digital implementation) as shown in FIG. 7B.

FIG. 8A shows a block diagram, with belonging waveforms of operation, of a DSM system for the addition of three or more DSM modulated pulse streams (digital implementation) as shown in FIGS. 8B and 8C.

FIG. 9 shows a proposed block diagram of a DSM system for the correlation of two analog input signals (digital implementation).

FIG. 10 shows a block diagram of a multi-purpose DSM IC chip.

DETAILED DESCRIPTION OF THE INVENTION Definition

Linear circuit networks are networks where linear network laws can be applied (addition, subtraction, multiplication by a constant, superposition, etc.). Nonlinear circuits are theoretical and implementation-specific and one is not able to apply linear network theory to these circuits; the same holds for mixed circuits.

Best Mode of Invention

Ten block diagrams of circuits are presented; herein shall be presented the best mode contemplated by the inventor.

How to Make the Invention

As can be amply seen from the drawings, every circuit presents an independent invention. Thus, it is necessary to describe every invention separately.

A full embodiment of the circuit for squaring a DSM pulse stream X_(n) is shown in FIG. 1A. Its operation is as follows:

Input analog signal x(t) is converted by means of DSM (1) into digital pulse stream X_(n) and fed directly into an XOR gate (3). Signal X_(n) is delayed by one clock period of DSM, X_(n-1), and delivered to the second input of XOR gate (3). After demodulation (4, LPF) a squared input waveform is obtained. Relevant waveforms of operations are shown in FIGS. 1C, 1D and 1E. If the input signal is sinusoid, then we have to see at output (4) a signal of double frequency (sin ωt)²=(1−cos 2ωt)/2. Signal (1), in FIG. 1C, is the sinusoidal input. Signal (2), in FIG. 1D, is the result of the squaring operation, and signal (3), in FIG. 1E, is the theoretical square of the input. For an input frequency of a 10 Hz sinusoid, we can see, in FIG. 1B, both spectral components, DC and AC at 20 Hz.

FIG. 2A presents the invention of a mixed mode DSM squaring circuit. The analog signal x(t) is delta-modulated (5) to get X_(n). At the same time analog signal x(t) is multiplied (mixed) with X_(n) in analog multiplexers 6 and 7 whose outputs are added and demodulated (8) to get signal p(t). Time waveforms are shown in FIGS. 2C, 2D and 2E. Upper signal (1), in FIG. 2C, is the sinusoidal input. Signal (2), in FIG. 2D, is the theoretical square waveform, and signal (3), in FIG. 3E, is the simulated result of the squaring operation. The spectral diagram, in FIG. 2B, shows the existence of DC (at zero) and AC (at 20 Hz) components for the input frequency of 10 Hz.

FIG. 3A presents the invention of a digital mode AC-DC converter when AC signal x(t) is delta-modulated (9). Delayed sequence X_(n-1) and un-delayed sequence X_(n) are fed in the XOR gate (12). At the same time X_(n) is shifted for 90 degrees (10). Output Y_(n) of the phase shifter (10) is fed to XOR (12). Second input of XOR (12) is connected to delayed signal Y_(n-1) of the phase shifter (10). Both outputs of XOR are added in Delta Adder (13) and low-pass filtered (14) to produce signal p(t). This circuit implements the well-known trigonometric identity (sin ωt)²+(cos ωt)²=1. ω—presents the angular frequency of AC input signal, and constant 1 (on right hand-side) DC value. Time waveforms are shown in FIGS. 3B and 3C. The upper signal (1) is AC input and lower signal (2) is the DC value, signal p(t). The same result is possible to obtain by connecting the output of XOR (12), with inputs X_(n) and X_(n-1), directly to the low-pass filter (14).

FIG. 4A shows a block diagram of the invention for the multiplication of two signals. Input analog signals x(t) and y(t) are added (15) and subtracted (16), then converted by synchronous delta modulators (17) and (18) to produce digital pulse streams (X_(n)+Y_(n)) and (X_(n)−Y_(n)) respectively. These two streams are then squared (according to the invention in FIG. 1A) and added to produce digital pulse stream S_(n)=X_(n)Y_(n). After demodulation (23) signal p(t)=x(t)y(t) is produced. Time waveforms of the multiplication of two sinusoidal signals with frequencies f₁=10 Hz and f₂=20 Hz are shown in FIGS. 4C and 4D. Signal (1), in FIG. 4C, is the theoretical multiplication and signal (2), in FIG. 4D, is the simulated one. In FIG. 4B we can see two spectral components located at the sum and difference of two frequencies [sin α*sin β=½ cos(α−β)−½ cos(α+β))]. The same circuit can be used for the squaring operation when x(t)=y(t).

FIG. 5A shows the block diagram of a digital implementation for the multiplication of two delta-modulated pulse streams A and B. Analog input signals x(t) and y(t) are converted by synchronous delta modulators (24) and (25) to produce X_(n) and Y_(n) DSM sequences. These signals are added and subtracted to produce signals A and B respectively. After the squaring operation (according to the invention in FIG. 1A), signals C and D are produced and subtracted in delta adder (31) to produce signal E. This signal is demodulated (32) and the squared signal p(t) is obtained. Time waveforms are shown in FIGS. 5C and 5D. Signal (1), in FIG. 5C, is theoretical, produced by multiplying two sinusoidal signals with frequencies of f₁=10 Hz and f₂=20 Hz. Signal (2), in FIG. 5D, is the result of simulation. Spectral content is shown in FIG. 5B. The same circuit can be used for the squaring operation when x(t)=y(t).

In FIG. 6A, the invention for root-mean-square-to-DC (RMS-to-DC) conversion is shown. Signal x(t) is delta modulated (33) and its output sequence X_(n) is AC-DC converted by means of the invention of FIG. 3A to produce signal A². The output of LPF (39) is fed back to switching multiplier M. The output signal of switching multiplier m(t) is fed into V_(ref) input of DSM. It is also possible to feed back the digital output of the delta adder (38). Simulation results in FIG. 6B are generated using digital feedback control (without analog multiplier M). Digital output of delta adder (38) is fed back to negative input of DSM (33). In FIG. 6B signal (1) presents the AC input signal and signal (2), in FIG. 6C, presents the demodulated RMS-DC value. The same result can be obtained if only output B of XOR gate (37) is fed back to Vref of DSM (33).

FIG. 7A shows the universal apparatus for the multiplication of a DSM sequence by a constant greater than one and a constant less than one. The output of delta modulator X_(i) is averaged first (41). The output of the average (41), signal F, is added according to the algorithm, W_(n)=W_(n-1)+F−LsgnW_(n-1), where L is a multiplication constant. If X_(i) has to be multiplied by two, then L=½. If X_(i) has to be divided by two, then L=2. After averaging (46), the demodulated signal x(t) is obtained. Relevant waveforms are shown in FIG. 7B. Waveform (1), signal x(t), is the amplified analog input x(t), signal (2). Waveform (3) is the demodulated DSM sequence X_(i) (non-amplified).

The invention in FIG. 8A is related to the addition of 3 or more DSM sequences. This invention overcomes the attenuation of a cascade of delta adders. FIG. 8A shows the case of the addition of three signals with frequencies f₁=3 Hz, f₂=2 Hz, f₃=0.6 Hz. Input signals are first DSM converted to produce sequences X_(n), Y_(n), and Z_(n) by means of delta sigma modulators 47, 48, 49 respectively. Sequences X_(n) and Y_(n) are added in the delta adder to produce sequence S₁. The last sequence Z_(n) is added to sequence W_(n-1). This is done to overcome the cascaded attenuation of two delta adders. In the case of an odd number of adders in the first layer, the second input of the last adder is terminated with idle sequence I₀. It is important to note that every level has only one D-FF for the generation of C_(n-1), the carry-out signal. In this example there are two levels of addition. The first level produces C_(n-1) ⁽¹⁾, and the second level produces C_(n-1) ⁽²⁾. The outputs of D-FF (52) and (54) are fed back to delta adders (50) and (53) respectively. Waveform (1), in FIG. 8B, is the theoretical addition of three signals of different frequencies, and waveform (2), in FIG. 8C, presents the simulated result.

FIG. 9 shows a block diagram of a DSM based correlator. The digital correlator is based on the direct processing of DSM streams X_(n) an Y_(n). The sum and difference of sequences is processed in delta adders (1) and (2). The outputs of delta adders E and G are squared (according to the invention in FIG. 1A) to produce sequences F and H. The sum of squares, C=F+H, is demodulated (66) to produce correlated signal c(t). The delay line is adjusted electronically to achieve maximum correlation. This correlator employs only one filter which is a significant savings as compared to classic correlators.

FIG. 10 shows a multi-purpose integrated circuit (IC) which incorporates relevant functions for the direct processing of a DSM pulse stream (linear, nonlinear and mixed analog/digital).

How to Use Invention

When DSM is used as an A/D converter, then any of the circuits for direct processing of DSM pulse stream can be used if needed. In particular, in low frequency applications such as environmental monitoring, seismic, bio-medical applications, control, instrumentation, etc., low-pass DSM is a well established A/D conversion procedure. Furthermore, DSM is low power consuming and dedicated circuits operate directly on a serial pulse stream. Only one wire is needed for internal and external connections and the use of one bit communication lines increases readability and reduces cost of the system. This is a significant advantage compared to existing 8 or 16 bit DSP hardware. Hardware and operation of circuitry are very simple and special manuals or software is not needed to operate circuits. Only data sheets with operating conditions and pin-out are needed. Eventual debugging is much simpler and faster compared to n-bit DSP hardware. VLSI is not a problem because of digital circuits' simplicity and the wide tolerance of DSM to component imperfections (±5%). In addition, because of the one bit (non-weighted) nature of the DSM stream, DSM DSP is not sensitive to catastrophic malfunctions as ordinary DSP. For example, if errors happen at the most significant or sign bit in an ordinary DSP system, then the system is out of order. This is not the case with a one bit processor because demodulation (DAC) is performed by a moving average filter. The main attributes of a DSM DSP system are high resolution of DSM ADC (24-bit), high signal-to-noise ratio and dynamic range (over 100 dB), low power consumption and the possibility of direct arithmetic operation on a DSM pulse stream. Thus, it will be appreciated by those skilled in the art that the present invention is not restricted to the particular preferred embodiments described with reference to the drawings, and that variations may be made therein without departing from the scope of the present invention as defined in the appended claims and equivalents thereof. The same circuitry can be employed for the direct processing of band-pass DSM (BPDSM).

NON PATENT LITERATURE DOCUMENTS

1. GORGON B. LOCHART, Digital Encoding and Filtering Using Delta Modulation, The Radio and Electronic Engineer, Vol. 42, No. 12, December 1972, pp. 547-551.

2. G. B. LOCHART, S. P. BABARY, Binary Transversal Filters Using Recirculating Shift Registers, The Radio and Electronic Engineer, Vol. 43, No. 3, March 1873, pp. 224-226.

3. ABRAHAM PELED, BEDE LIU, A New Approach to Realization of Nonrecursive Digital Filters, IEEE Transaction on Audio and Electroacoustics, Vol. AU-21, No. 6, December 1973, pp. 477-484.

4. ABRAHAM PELED, BEDE LIU, A New Hardware Realization of Digital Filters, IEEE Transaction on Acoustics, Speech, and Signal Processing, Vol. ASSP-22, No. 6, December 1974, pp. 456-462.

5. D. LAGOYANNIS, Multiplier for Delta-Modulated Signals, Electronics Letters, 14^(th) Sep. 1978, Vol. 14, No. 19, pp. 614-616.

6. JOSEPH L. LOCICERO, DONALD L. SCHILING, JOSEPH GARODNICK, Realization of ADM Arithmetic Signal Processors, IEEE Transaction on Communications, Vol. COM-27, No. 8, August 1979, pp. 1247-1254.

7. N. KOUVARAS, Operations on Delta-Modulated Signals and their Applications in the Realization of Digital Filters, The Radio and Electronic Engineer, Vol. 48, No. 9, September 1978, pp. 431-438.

8. N. KOUVARAS, A Special-Purpose Delta Multiplier, The Radio and Electronic Engineer, Vol. 50, No. 4, April 1980, pp. 156-157.

9. N. KOUVARAS, Some Novel Elements for Delta-Modulated Signal Processing, The Radio and Electronic Engineer, Vol. 51, No. 5, May 1981, pp. 241-249.

10. N. KOUVARAS, Novel Multi-Input Signal-Processing Networks with Reduced Quantization Noise, Int. J. Electronics, 1984, Vol. 56, No. 3, pp. 371-378.

11. N. KOUVARAS, J. KARAKATSANIS, A Technique for a Substantial Reduction of the Quantization Noise in the Direct Processing of Delta-Modulated Signals, Signal Processing, Elsevier Publishers, Vol. 8, No. 1, February 1985, pp. 107-119.

12. N. KOUVARAS, Modular Network for Direct Complete Addition of Delta-Modulated Signals with Minimum Quantization Error, Int. J. Electronics, 1985, Vol. 59, No. 5, pp. 587-595.

13. D. LAGOYANNIS, K. PEKMETZI, Multipliers of Delta-Sigma Sequences, The Radio and Electronic Engineer, Vol. 51, No. 6, June 1981, pp. 281-286.

14. DJ. ZRILIC, K. ZANGI, A. MAVRETIC, M. FREEDMAN, Realization of Digital Filters for Delta-Modulated Signals, 30^(th) Midwest Symposium on Circuits and Systems, Syracuse University, Aug. 16-18, 1987.

15. M. FREEDMAN, DJ. ZRILIC, Nonlinear Arithmetic Operations on the Delta Sigma Pulse Stream, Signal Processing, Vol. 21, 1990, pp. 25-35.

16. D. G. ZRILIC, Circuits and Systems Based on Delta Modulation (Book), Springer, 2005, ISBN 3-540-23751-8.

17. PING WAH WONG, ROBERT M. GRAY, FIR Filters with Sigma-Delta Modulation Encoding, IEEE Transaction on Acoustic Speech and Signal Processing, Vol. 18, No. 6, June 1990, pp. 979-990.

18. S. HORIANOPOULOS, V. ANASRASSOPOULOS, T. DELIYANNIS, Design Technique for Hardware Reduction in Delta Modulation FIR filters, Int. J. Electronics, 1991, Vol. 71, No. 1, pp. 93-106.

19. DAVID A. JOHNS, DAVID M. LEWIS, Design and Analysis of Delta-Sigma Based IIR Filters, IEEE Transaction on Circuits and Systems-II Analog and Digital Signal Processing, Vol. 40, No. 4, April 1993. 

What is claimed:
 1. FIG. 10 presents a delta-sigma (DS) modulated digital signal processor (DSP) chip which is comprised of independent inventions shown in FIGS. 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A, and 9A. These inventions can be integrated on the single integrated circuit (IC) chip as shown in FIG.
 10. This DS modulated DSP chip comprises of interface unit (multiplexed sensor network); low-pass or band-pass DS modulator; and functional unit for direct processing of a low-pass or band-pass DS modulated pulse stream. The functional unit comprises of: digital circuit for squaring or rectifying operation of delta modulated pulse stream; mixed analog/digital circuit for squaring operation of delta modulated pulse stream; digital rectifying circuit for alternate current-to-direct current (AC-to-DC) conversion; multiplier of two delta modulated pulse streams with analog addition and subtraction of two signals at the input of DS modulator; digital multiplier of two DS modulated sequences; root-mean square to direct current (RMS-to-DC) converter; digital circuit for multiplication of DS modulated pulse streams with a constant greater or less than one; circuit for addition three or more DS modulated sequences; digital correlator circuit for correlation of two DS modulated sequences.
 2. Functional unit according to claim 1 consists of independent digital circuit for squaring or rectifying operation. This circuit can be integrated separately for multi-purpose use or it can be integrated on one chip with the rest of the circuits with external addressing as shown in FIG.
 10. 3. Functional unit according to claim 1, includes an independent circuit for mixed analog/digital squaring operation. It can function separately as an integrated circuit (IC), or integrated in a programmable functional unit with external addressing as shown in FIG.
 10. 4. Functional unit according to claim 1, includes a digital alternate current-to-direct current (AC-to-DC) converter. It can operate as an independent rectifying IC, or it can be integrated into a programmable functional unit as shown in FIG.
 10. 5. Functional unit according to claim 1 includes multiplier of two DSM sequences, where analog inputs are added and subtracted and their sum and difference is delivered to the delta modulator for further processing. It can be integrated as a separate IC chip, or integrated into a programmable functional unit as shown in FIG.
 10. 6. Functional unit according to claim 1 includes digital multiplier of two DSM sequences. This circuit can be integrated as a separate IC chip, or integrated into a programmable functional unit as shown in FIG.
 10. 7. Functional unit according to claim 1 includes circuit for RMS-to-DC conversion. It can be integrated as a separate chip, or integrated into a programmable functional unit as shown in FIG.
 1. 8. Functional unit according to claim 1 includes circuit for multiplication by a constant (greater or less than one). This algorithmic circuit can be integrated as a standalone chip, or it can be integrated into a programmable functional unit as shown in FIG.
 10. 9. Functional unit according to claim 1 includes circuit for addition of multiple input signals. This circuit has the capability of overcoming attenuation of cascaded delta adders and it can be designed as a standalone IC chip or it can be integrated into a programmable functional unit as shown in FIG.
 10. 10. Functional unit according to claim 1 includes circuit for correlation of two DSM signals. It can be integrated as a standalone IC chip or integrated into a programmable functional unit as shown in FIG.
 10. 